| Summary: | 碩士 === 龍華科技大學 === 工程技術研究所 === 97 === Air pollution in coal-fired power plant is still an issue around the world. In past several decades NOx, SOx and heavy metals could be controlled effectively from the emission of power plant. Recently, emission of carbon dioxide and mercury became significant from environmental viewpoint. In USA, Congress and EPA are determined to regular mercury emissions by the law since mercury is harmful for human heath. Due to this, how to control and measure mercury becomes important in coal-fired power plants, in which sampling and analysis methods play an important role on the control and measurement of mercury emission in power plants. In literature, several methods were proposed for both long-term and short-term applications depending on the requirements of power plants.
In this study, Ontario Hydro method, sorbent trap method (adsorption capturing method) and continuous mercury monitor were used for sampling and analyzing on-site in coal-fired plant. The concentrations of elemental mercury (Hg0), oxidized mercury, and total mercury can be determined successfully from sampling points before and after the equipment. Due to this, the form of mercury in coal-fired plant could be identified.
During non-ozone season the ratio of elemental mercury at APH(Air Preheater) outlet was 69.82%, while during ozone season the ratio of elemental mercury, according to the flowing flue-gas through SCR(Selective Catalytic Reduction) and at APH outlet, became 6.79%. On the other hand, the removal efficiencies of mercury for APCD(Air Pollution Control Device) in coal-fired power plant were 56% and 90% for non-ozone season baseline test and ozone season baseline test, respectively.
In continuous mercury monitor test, calibrations for each system were carried out successfully. A combination of the continuous mercury monitor method and Ontario Hydro method was used to conduct the Relative Accuracy Test Audit (RATA). The results showed that the continuous mercury monitor was passed the test and can be used as long-term monitoring for the continuous emission of mercury in coal-fired power plant.
The sorbent trap method, Ontario Hydro method, and continuous mercury monitor were used to proceed the RATA test; the results showed that all of them were passed the tests, in which the reference method can be replaced by the sorbent trap method used as single point sampling in batch form since the system is simpler as compared with that reference method.
|
|---|
